1. Field of the Invention:
This invention relates to wood fiber crumbles prepared from one or more of western red cedar, red alder, larch, Ponderosa pine, lodgepole pine, sugar pine, Engelmann spruce, Sitka spruce, Douglas fir, western hemlock and mountain hemlock, and a method for making the same. The wood fiber crumbles are intended particularly for use as animal litter, for example, a cat litter; the crumbles can also be used for a petroleum spill absorbent, a floor sweeping material, and a mulch.
2. Description of the Prior Art:
An animal litter for domestic pets such as cats, dogs, mice, gerbils, birds, and the like, should have the following desirable qualities: high absorbency of animal excretions, ability to rapidly minimize unpleasant odors, nonadherence to animal paws and fur, biodegradability, and low cost. In addition, the litter should contain an inhibitor of the growth of microorganisms; it should repel insect pests, for example, fleas and moths; and it should contain little or no dust. Preferably, the manufacture of the litter should utilize industrial or agricultural waste products to alleviate the problem of waste disposal.
Clay materials and other inorganic absorbents have long been used as animal litter, but, except perhaps for their low cost, these lack the above-listed desirable qualities. A variety of fibrous organic absorbent materials have also been used in animal litter, for example, wood fiber products, peat moss, corn cob pulp, beet pulp, peanut hulls, sugar cane stalks, etc., and chlorophyll containing plants such as alfalfa. See, e.g., Lojek, et al., U.S. Pat. No. 4,676,196. Although such organic absorbent materials are generally biodegradable, they are not sufficiently effective in minimizing odor, nor are they generally effective in inhibiting the growth of microorganisms or in repelling insect pests.
To enhance the odor minimizing capability of such fibrous organic materials, Carlberg, U.S. Pat. No. 4,157,696, described a method for intimately mixing cellulose fibers, e.g., powdered agricultural wastes, with flyash, and pelletizing the mixture, whereby the flyash effectively deodorized animal excretions.
White, U.S. Pat. No. 3,828,731, described the addition of chlorophyll containing compounds and microbial inhibitors to high purity alphacellulose paper stock fibers as an effective way to restrict and minimize odors in animal litter. Ground sagebrush particles and sagebrush oil were reported by Stapley, U.S. Pat. No. 4,355,593, as effective for minimizing odors when added to a variety of absorbent litter materials. A number of heterocyclic antimicrobial compounds are known, but these are difficult to substantively bind to cellulosic fibrous material; nevertheless, Brasseur, U.S. Pat. No. 4,618,496, described a method for substantively binding antimicrobial heterocylcic compounds to peat moss to create a composition useful for absorbing body fluids.
The present invention seeks to achieve all the above-listed desirable qualities of an animal litter by utilizing wood wastes, that is, bark, sawdust, lumber and/or chips of western red cedar, red alder, larch, Ponderosa pine, lodgepole pine, sugar pine, Engelmann spruce, Sitka Spruce, and Douglas fir in the manufacture of wood fiber crumbles. In particular, the invention takes advantage of the unique characteristics of each of these kinds of wood by combining them to achieve the desired goals. For instance, western red cedar has a natural oil that repels fleas and several types of moths. Red alder has a very high nitrogen content. Ponderosa pine has oils that are antimicrobial. Although the unique characteristics of these woods have been known and utilized previously in animal litter, they have not heretofore been combined in a single litter. As a first example, Rowell, U.S. Pat. No. 4,258,659, described an apparatus and method for making animal litter from super dry particles of softwood waste matter, using as examples of the types of litter material white pine, red pine, jack pine, Norway Pine, and the like. As a second example, Harsh, et al., U.S. Pat. No. 4,386,579, disclosed an animal litter consisting of comminuted cedar in a discrete bottom layer and an overlying layer of absorbent soil, such as diatomaceous earth and clays, wherein the soil and cedar were in unmixed, unbound relationship. As a third example, Fry, U.S. Pat. No. 3,941,090, described a composition and process for making pellets of cedar particles admixed with dehydrated alfalfa binder, which pellets have insect-repellant characteristics.
Billings, U.S. Pat. No. 4,788,936, disclosed a method for bedding animals and treating sludge using aspen or poplar barkbased pellets. High absorbency of animal excretions was thereby achieved, but no combination of antimicrobial and insect pest repelling wood oils such as that of the present invention was utilized.
Moreover, although animal litter in the form of pellets is well known in the prior art, this invention achieves a marked increase in absorbency of liquids by the additional step of grinding the pellets to wood fiber crumbles.